The SASE3 Variable Polarization project is intended to offer polarization control of the X-ray FEL pulses at the European XFEL. The project was completed in early 2022. During the winter shutdown 2021-2022, all four APPLE-X helical undulators were placed in the tunnel and first lasing was achieved in April 2022. Unfortunately, further use of the helical afterburner proved impossible, as the encoders used to position the magnetic structures of the undulator were damaged by radiation. To carry out repairs, all undulators were removed from the tunnel in the summer 2022, and investigations were carried out to determine the cause of the radiation damage. This article presents measures taken to minimize further radiation damage in order to ensure the continued operation of the helical afterburner.